Centrifugal pump

ABSTRACT

A centrifugal pump is disclosed which comprises a pump housing containing a centrifugal pumping assembly. The housing has an access opening at one side of the pumping assembly and the parts of the pumping assembly are detachably supported within the housing for removal through the access opening. A number of different pumping assemblies can be supported in the housing so that various pumping characteristics can be obtained.

United States Patent [1 1 McFarlin I CENTRIFUGAL PUMP [75] Inventor: Stanley B. McFarlin, Jeromesville,

Ohio

[73] Assignee: The Gorman-Rupp Company,

Mansfield, Ohio [22] Filed: Mar. 24, 1971 [21] Appl. N0.: 127,446

[52] U.S. C1 415/53, 415/197, 415/201 [51] int. Cl. F04d 9/02, F04d 7/00, F04d 29/40 [58] Field of Search 415/201, 196, 197, 415/219, 53

[56] References Cited UNlTED STATES PATENTS 1,727,703 9/1929 Hause et al. 415/196 2,365,058 12/1944 Crawford 415/197 2,580,347 12/1951 Eggleston 415/53 1,278,721 9/1918 Nachenius 415/201 2,228,207 1/1941 Forssell 415/201 2,849,960 9/1958 Olmstead et al 415/201 Primary Examiner-Henry F. Raduazo AttorneyWatts, Hoffmann, Fisher & l-leinke [57] ABSTRACT A centrifugal pump is disclosed which comprises a pump housing containing a centrifugal pumping as sembly. The housing has an access opening at one side of the pumping assembly and the parts of the pumping assembly are detachably supported within the housing for removal through the access opening. A number of different pumping assemblies can be supported in the housing so that various pumping characteristics can be obtained.

18 Claims, 5 Drawing Figures Pmmm w I 3.778.181

sum 1- ar 3 INVENTOR. STANLEY .BM FARL/N A TTOPNEYS PAIENIEHBEBI H 3378.181

' sum 2 or a INVENTOR. STANLEY B. M 'FARL/ N ATTORNEYS minnow 1w 3.778.181

INVENTOR. STANLEY 5. M FARL/A/ A Tram/Era CENTRIFUGAL PUMP BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates generally to the pump art, and more specifically to self-priming centrifugal pumping apparatus.

2. The Prior Art A typical self-priming centrifugal pump is generally comprised of a large housing which has several internal chambers and communicating flow passages. Such a housing is constructed to define a suction chamber or reservoir connected to a suction inlet pipe, and a pressure or discharge chamber connected to an outlet pipe. A volute scroll which defines an impeller chamber including a cutwater is also provided in the housing. An impeller is rotatable within the scroll to establish a suction flow of liquid into the suction chamber through an intake check valve and to force the liquid past the cutwater into the discharge chamber and out of the pump at the desired flow rate and head. An annular wear plate which defines an internal port is mounted adjacent the impeller, and the liquid is forced through the wear plate port into the eye of the impeller during operation of the pump.

Self-priming pumps as described above are furnishe in different sizes, and each size pump can be made to exhibit varying hydraulic characteristics, i.e., flow rate and head. The flow rate and head depend upon a number of factors, including the width and diameter of the impeller, the impeller speed, the size of the impelller eye, and the geometry and size of the volute scroll.

In designing and constructing the conventional pumps to suit a users specific requirements, it has been necessary for a manufacturer to make and stock several different housingconfigurations for each pump size. One reason for this is that the volute scroll, or at least a major portion of the scroll, has been made as an integral part of the housing. Because of the many different housing configurations which have been required to provide pumps having a range of performance characteristics, and because of the fact that any particular housing configuration may be needed very infrequently, it has not been practical to produce the housingsby economical methods of manufacture, as by permanent mold casting. The usual practice has been to make the housingsby sand casting using separate tooling for each configuration.

Another problem presented by prior art constructions is that of servicing the pumps to replace worn parts, such as impellers, wear plates, seals and cutwaters, and to remove trash or debris trapped in the pump housings. In many instances it is necessary to discon nect the inlet and outlet plumbing and to disassemble the pump housing in order togain access to its interior. When replacing certain parts such as seals, it is often necessary to dismantle the entire pump. All of these maintenance operations are difficult and timeconsuming.

A further difficulty encountered in the servicing of conventional pumps hasbeen in connection with the construction andlocation of the inlet check valve. The

inlet check valve is subject. to being blocked and prevented from closing, and in such a case the pump may lose its prime. Many conventional valves are constructed and assembled so that it is necessary to disconnect and remove fittings in the inlet plumbing when servicing the valve.

Some centrifugal pumps have been constructed so that the housing has a removable cover plate which facilitates maintenance. In a commercially available pumps of this type, the suction pipe connection is radially off-set from the eye of the impeller and the suction chamber of the housing has a complex internal shape defining a tortuous fluid flow path leading to the eye of the impeller. Such housings are particularly expensive to make. The complex internal shape of the housing is also the cause of inefficiencies in the operation of the pump. The internal chambers, passageways and ports through which the liquid flows restrict the potential output and cause losses in flow rate and pumping pressure.

Another problem of prior art centrifugal pumps has resided in the construction of the cutwater portion of the volute scroll. The cutwater is the last part of the scroll to be swept across by the impeller as its crosses the scroll outlet opening. The cutwater is impinged upon by particles and debris carried by the liquid and tends to wear more rapidly than other portions of the scroll. Since the ability of a pump to prime depends to a large extent upon the geometry of the cutwater, untoward wear of this portion of the scroll can result in a complete loss or decrease in efficiency of the priming capability.

SUMMARY OF THE INVENTION The present invention provides anew and improved centrifugal pumping apparatus which simplifies the problems involved in designing and constructing pumps to suit a users specific requirements, and which can be easily serviced in the field.

An important feature of the invention resides in the construction of the pump housing which contains the impeller, volute scroll, wear plate and shaft seal. The pump housing defines an access opening in one side and a removable closure member which seals the access opening. All of the pump parts are detachably mounted in the housing so that they can-be readily removed through the access opening without the necessity of disconnecting the suction and/or discharge plumbing. It is therefore possible to quickly and easily remove and replace worn parts when maintenance of the pump is required. The access opening of the housing and the manner in which the pump parts are assembled also make it easy to clean out the pump if it becomes clogged by debris when in use.

The new pump is constructed so that a universal housing design accommodates various combinations of wear plates, volute scrolls, impellers, seal configurations, etc. as are requiredto assemble pumps exhibiting different hydraulic characteristics. Since a single housing configuration can be used to assemble a range of pumps having different hydraulic: characteristics, it is possible to produce the housings in quantity by economical methods of manufacture, as by permanent mold casting.

All of the foregoing advantages are obtained while providing a housing of simplified design characterized by a suction inlet passage which is in substantial alignment with the eye of the impeller. The straight-in? inlet passage results in a pump having a more efficient operation than prior art pumps embodying housings with complex internal shapes that restrict output and cause losses in flow rate and priming pressure. The advantageous inlet passage arrangement is obtained while providing a large reservoir in the housing that makes it possible to accomplish priming even when the suction inlet valve is damaged or is prevented from closing.

While the invention in its more preferred aspects relates specifically to self-priming centrifugal pumps, the new housing structure is such that it can be used as part of a straight centrifugal flooded pump. Since the housing is constructed to receive a separable volute scroll, a centrugal flooded pump is constructed merely by mounting an impeller in the housing in the absence of a volute scroll. This advantageous feature is thus obtained by making the volute scroll separate from the housing and avoiding the several chambers and internal passages of conventional housing constructions.

Another important feature of the invention resides in the construction of the scroll. The new scroll is defined by a pair of cast scroll members removably mounted in the pump housing. The scroll defines an outlet opening and a volute wall. Part of the volute wall and part of the outlet opening are formed by one scroll member. The cutwater and remaining volute wall are formed by the second scroll member which can be removed and replaced through the housing access opening independently of the first mentioned scroll member. In the preferred embodiment of the invention, the scroll member forming the cutwater is carried by the access opening closure member and is coated with a wear-resistant material, such as rubber or the like, in order to increase the life of the cutwater. The removability of the second scroll member simplifies maintenance, makes it easy to clean out the volute, and prolongs the life of the scroll by enabling replacement of the cutwater.

Still another feature of the invention resides in the provision of a suction inlet valve which is assembled between a flanged inlet opening of the pump housing and a flange on the suction pipe. The valve is bolted in place between the flanges and can be easily removed without disturbing the suction plumbing.

Other features and advantages and a fuller understanding of the invention will be had by reference to the accompanying drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective exploded view with portions broken away of a pump constructed according to the present invention;

FIG. 2 is a vertical cross sectional view of an assembled form of the pump shown in FIG. 1;

FIG. 3 is a cross sectional view seen approximately from the plane indicated from the line 33 of FIG. 2 with portions broken away;

FIG. 4 is an elevational view of an inlet valve seen approximately from the plane indicated by the line 44 in FIG. 2; and,

FIG. 5 is a cross sectional view seen from the plane indicated by the line 55 of FIG. 4.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT A self-priming centrifugal pump constructed according to the preferred embodiment of the present invention is shown in FIGS. 1 and 2. The pump 10 includes a pump housing 12 containing a centrifugal pumping assembly 14. The pumping assembly 14 comprises an impeller generally designated at 15, a scroll 16 disposed circumferentially about the impeller 15, and a wear plate 17 which is disposed at one axial side of the impeller. The impeller 15 is driven by a rotatable shaft 18 which extends into the housing 12. The shaft 18 may be turned by a suitable motor or engine (not shown). The pumping assembly 14 draws liquid into the housing 12 through a suction pipe 19 and inlet assembly 20 and discharges liquid from the housing 12 through a discharge pipe 22.

The housing 12 defines a pumping chamber 24 in which the assembly 14 is disposed and which enables the pumping assembly to be self-primed when necessary. The chamber 24 is defined by a housing end wall portion 26 which defines an opening 27 in the housing. The shaft 18 is rotatably supported in the opening 27. An embossed area 28 surrounds the opening 27 and provides supports for shaft bearings 29 and a shaft seal assembly 30. A second housing wall portion 31 is spaced axially from the housing wall portion 26 and defines an inlet opening 32 in which the inlet assembly 20 is supported. In the preferred embodiment of the invention, the openings 27, 32 are substantially coaxial and the axis of rotation of the impeller 15 extends along their centers.

A liquid discharge opening 34 is defined at the upper end of the housing 12 and this opening is surrounded by a flange 36 formed integrally with the housing and which is bolted to a discharge pipe flange (FIG. 2). The housing 12 further defines an access opening 38 which is laterally spaced from the axis of rotation of the impeller and through which access to the interior of the housing 12 is obtained. The opening 38 is closed by closure structure generally indicated at 40 which is described in greater detail below.

Referring now to FIG. 2 the inlet assembly 20 is detachably supported in the opening 32 and defines an inlet passage 41 which directs liquid from the suction pipe 19 to the eye of the impeller 15 through the housing wall portion 31. The assembly 20 is constructed so that the inlet passage 41 is relatively straight and is in substantial alignment with the impeller eye so that liquid flowing into the impeller through the inlet passage 41 is substantially unimpeded. The assembly 20 includes a body 42 and an inlet check valve 44. The body 42 is a generally tubular member having an annular mounting flange 46 which is snuggly received in the opening 32. An O-ring seal 48 is compressed between the flange 46 and the opening 32 to seal the juncture of the body 42 and the housing 12. The body is attached to the housing 12 by screws 50 which extend through holes in embossed legs 52 which project radially beyond the flange 46. The holes are alignable with threaded openings 53 in the housing (FIG. 1). A body end 54 projects into the housing 12 and defines an annular surface 56 coaxial with the axis of rotation of the impeller 15. An outwardly projecting body end 58 forms a mounting flange 59 by which it is connected to the suction pipe 19.

The valve 44 is connected between the flange 59 and a flange 190 on the suction pipe. The valve 44 is removable as a unit for replacement or repair. Referring now to FIGS. 4 and 5 the valve 44 includes an annular valve seat member 60 which is generally wedge-shaped to provide an inclined face or seat 61a and a planar face 61b which is flush with and sealingly engaged with the flange 19a. The inlet passage 41 extends through the seat member 60. A second annular wedge-shaped rubber valve body 62 abuts the member and carries an integral flapper valve member 64 which extends along the seat 61a and is biased by the force of gravity into engagement with the seat 61a to prevent liquid flow through the body 42 away from the housing 12. The body 62 has an annular face 63a which seats against the seat face 61a and a planar face 63b which is flush with and sealingly engaged with the flange 59. The valve member 64 is preferably formed by a rubber tonguelike member 64a having steel backing members 64b bonded in place on it. The tongue member 64a is continuous with the body 62 and is connected to the body by a hinge 65. A rigid annular split ring 66 surrounds the members 60, 62 for retaining them together and for limiting compression of the valve 44. When the pumping assembly is operating, the liquid flowing through the suction pipe 19 into the housing 12 forces the valve member 64 away from the seat 61a so that the flow of liquid into the pump is unimpeded by the valve.

The valve assembly 44 is maintained in place by bolts 68 which extend through bolt holes in the flanges on the body 42, aligned bolt holes in the valve 44, and bolt holes in the suction pipe flange 19a. The bolts 68 are tightened to compress the valve 44 between the flanges so that the faces 61b and 63b are sealed against the repsective adjacent flanges 19a, 59. The axial extent of the split ring 66 is smaller than the axial extent of the valve 44 in an uncompressed condition. As shown in FIG. 5 the axial extent of the ring 66 is slightly greater than the maximum axial dimension of the valve seat member 60 so that compression of the member 62 is assured. The split ring 66 thus limits compression of the valve due to tightening of the bolts 68 so that the resilient material of the body 62 is not damaged by extrusion. The ring 66 also assures uniform sealing pressures about the valve when all of the bolts are tightened down.

When the bolts 68 are removed the valve 44 is slid from between the flanges as a unit for replacement or repair. Because the faces 61b, 63b of the valve are parallel and flush with the flanges 19a and 59, respectively, the entire valve 44 is readily slid from between the flanges when the bolts 68 are removed. This eliminates disassembly of any of the inlet plumbing fixtures in order to service the valve 44. The construction of the valve member 64 is narrow so that no part of the valve member 64 projects axially beyond the faces 61b or 63b which could otherwise interfere with removal of the valve. The split ring 66 serves as a retainer to maintain the valve 44 assembled after removal from between the flanges.

The pumping assembly 14 is installable in the housing through the access opening 38 during manufacturing and is removable through the access opening for servicing. The closure arrangement 40 for the access opening 38 includes a closure member 78 having a peripheral flange 76 which seats over the access opening, and a clamp 78 for maintaining the closure member sealed against the housing 12. The clamp 78 includes a clamp bar 80 having a hook construction 82 at one end which extends around the flange 76 and engages a projection 84 on the housing 12 adjacent the opening 38. An opposite clamp bar end 86 extends into engagement with a hook-like projection 88 which extends from the housing adjacent the discharge. flange 36. A clamp screw 90 is disposed in a tapped hole in the clamp bar and engages the member 74 to urge it into position over the access opening.

The scroll 16 is formed by two scroll parts each detachably connected to the housing and which are insertable and removable through the access opening 38. The scroll part 92 includes a hub 94 having a generally radially extending flange 96 and a volute wall defining portion 98 which extends axially from the flange 96 and about a circumferential segment of the impeller 15. The hub 94 is attached to the housing wall portion 26 by screws 100 (only'one of which is illustrated) which extend through the housing wall and into tapped holes in embossed areas of the hub. The volute wall portion 98 has a bottom priming inlet opening 102 (FIG. 1) through which liquid enters the volute during priming, and a discharge opening lip 104 through which liquid is discharged from the impeller into the housing 12.

Referring now to FIG. 3, the second scroll part 106 is formed integrally with the closure member 74 and defines a volute wall portion 108 extending about a circumferential section of the impeller. The opposite ends of the volute wall portion 108 mate with opposite ends of the volute wall portion 98 when the closure member 74 is in its operative position closing the access opening 38. The upper end of the volute wall portion 108 provides a cutwater 110 at the discharge of the scroll means. The cut-water region in a centrifugal pump is subjected to errosion and/or abrasions from debris entrained in the pumped liquid.

In the preferred embodiment therefore, the second scroll part is covered by a suitable abrasion and wear resistant plastic or rubber coating 112 which extends continuously about the second scroll part 106 along the volute wall portion 108 as well as extending along the peripheral flange 76. The rubber coating 112 provides a seal between the flange 76 and the housing 12 surrounding the access opening.-

The wear plate 17 is positioned adjacent the face of the impeller 15 and joins with the scroll to substantially enclose the impeller. The wear plate 17 is defined by a cylindrical support body 114 having one end seated on the annular surface 56 of the inlet body 42. An annular flange 116 at the opposite end of the support body extends radially along the face of the impeller and its periphery lies closely adjacent the scroll periphery. A seal member 118 extends between the scroll and the flange 116. The flange l 16 defines an inlet port 120 adjacent the eye of the impeller.

The wear plate 17 is detachably connected to the body of the inlet assembly 20 and is removable from the housing through the access opening 38. The wear plate body 114 includes ribs 122 (FIG. 1) which extend along its exterior and defines tapped holes 124 which receive screws 126 extending through holes 128 in the inlet assembly body 42 and the mounting flange 46. The heads of the screws are located on exterior surfaces of the inlet assembly so that they can be loosened or tightened without gaining access to the inside of the pipe housing 12. When the screws are removed, the wear plate is free to be withdrawn from the housing through the access opening. If debris has lodged in the inlet assembly or at the eye of the impeller, or in the scroll, removal of the wear plate and the scroll part 106 will usually permit access to the blockage without requiring further disassembly of the pump.

The pumping assembly 14 can be completely disassembled and removed from the housing 12 by a serviceman. Assuming, for example, that a serviceman finds that the seal 30 must be replaced, the clamp screw 90 is loosened and the clamp bar 80 is removed from the housing 62. The closure member 74 and the integral scroll part 106 are withdrawn from the access opening 38 to expose the impeller 15, the scroll part 92 and the wear plate 16. The wear plate mounting screws 126 are removed from the inlet assembly and the wear plate 17 is withdrawn through the access opening. The impeller 15 is then turned off of the threaded end of the drive shaft 18. The scroll mounting screws 100 are removed and the scroll part 92 is taken from the shaft 18 and withdrawn from the housing. The seal'assembly 30 is then exposed for removal and replacement.

If additional access to the interior of the housing is desired, the inlet assembly 20 can be removed to enable the serviceman to reach into the housing from different angles. This is accomplished by detaching from the suction pipe 19 and removing the screws 50 which connect the inlet assembly to the housing.

Another important feature of the new pump resides in the adaptability of the housing to various pumping assemblies so that a series of pumps using a common housing configuration can be produced. Each different pumping assembly of a series can be installed in the housing 12 without requiring modifications of the inlet assembly 20 or the housing 12. The different pumping assemblies have different impeller configurations and dimensions so that different pumping characteristics are produced. The scrolls and wear plates associated with one impeller configuration are thus not necessarily the same as the scroll and wear plate configurations for another impeller. The various pumping assemblies need only be constructed so that the wear plates, and scroll means of the individual assemblies are connectable in the housing 12. Hence, each wear plate will have screw holes alignable with the screws 126 extending through the inlet assembly. Each scroll will be alignable with the screws 100 extending through the housing wall portion 26. Each impeller is constructed for threading onto the shaft 18. Where the closure member and second scroll part are integral, as described above, the closure member is constructed to fit a given one of the alternate pumping assemblies, but the pump housing 12 need not be modified.

While a single embodiment of the invention has been illustrated and described herein in considerable detail, the present invention is not to be considered limited to the precise construction shown. It is the intention to cover hereby all adaptations, modifications and uses of the invention which come within the scope of the appended claims.

1 claim:

1. In a centrifugal pump having a pumping assembly comprising a rotatable impeller, an impeller drive shaft, scroll means circumferentially surrounding the impeller, and plate means on an axial side of the impeller; the improvement comprising a pump housing for said pumping assembly comprising:

a. a first housing wall portion defining an inlet openb. a second housing wall portion defining an impeller drive shaft supporting opening in which the impeller drive shaft is supported for rotation about an axis extending through said first and second walls;

c. a discharge opening through which liquid is discharged from said housing;

d. at least part of the scroll means detachably connected to one of said first and second housing wall portions;

e. the other of said first and second housing wall portions supporting the plate means by a detachable connection;

f. a third housing wall portion spaced laterally from said axis and defining an access opening through which the impeller, the plate means and said at least part of the scroll means are removable from said housing; and,

g. closure means detachably connected to the housing across said access opening.

2. The pump claimed in claim 1 wherein said closure means comprises a closure member engaged with said housing across said access opening and a clamp device for urging said closure member into sealing engagement with said housing.

3. The pump claimed in claim 2 wherein one of said first and second wall portions of said housing defines openings through which mounting members extend to said at least part of the scroll means, said mounting members being accessible from the exterior of said housing to permit said at least part of the scroll means to be detached from the housing wall portion.

4. The pump claimed in claim 1 wherein said housing further includes a liquid inlet assembly supported by said first housing wall portion, said inlet assembly defining a supporting surface for said plate means in said housing.

5. The pump claimed in claim 4 wherein said plate means is connected to said inlet assembly by fasteners which extend from said plate means through said assembly to a location on the exterior of said housing, said fasteners detachable from said exterior location.

6. In a centrifugal pump:

a. a pump housing defining a chamber having an inlet opening and a discharge opening;

b. a pumping assembly supported by said housing in said chamber for drawing liquid through said inlet opening and discharging liquid from said housing through said discharge opening;

c. said pumping assembly comprising;

1. an impeller supported for rotation about an axis extending through said housing;

2. scroll means extending circumferentially about said impeller and defined by at least one scroll member detachably connected to said housing;

3. a wear plate member detachably supported in said housing adjacent an axial side of said impeller and defining an opening through which inlet fluid flows to said impeller; and,

(1. said housing defining an access opening along a side thereof laterally spaced from said axis, and said wear plate member, said at least one scroll member and said impeller removable from said chamber through said access opening.

7. The pump claimed in claim 6 wherein said at least one scroll member is maintained in position in said housing by a clamp device secured to an exterior. wall of said housing.

8. The pump claimed in claim 7 wherein said at least one scroll member defines a cut water of said scroll means, and further including a coating of nonmetallic abrasion resistant material extending over at least said cut water portion of said one scroll member.

9. The pump claimed in claim 8 wherein said one scroll member is integral with a closure member for said access opening, said coating of resilient material extending over at least part of said closure member to seal the juncture of said closure member and said housing about said access opening.

10. In a centrifugal pump:

a. a housing defining a chamber;

b. said housing having an inlet passage, a discharge opening, a shaft opening, and an access opening;

c. a rotatable shaft extending into said housing through said shaft opening;

d. an impeller removably mounted on said shaft in said chamber for rotation on an axis;

e. scroll means removably connected to said housing and defining an impeller chamber in which said impeller is disposed;

f. a wear plate removably mounted in said chamber adjacent said impeller and defining a port communicating said inlet passage to the eye of said impeller;

g. said access opening being laterally spaced from said axis so that said impeller, scroll means and wear plate can be removed from said housing chamber without disconnecting plumbing communicating with said inlet passage and said discharge opening; and,

h. removable closure means for closing said access opening.

11. A pump as claimed in claim 10 wherein said inlet passageextends in substantial alignment with said axis.

12. A pump as claimed in claim 10 including a tubular body defining said inlet passage, and means detachably connecting said body to a wall portion of said housing.

13. A pump as claimed in claim 10 wherein said scroll means comprises a first member detachably connected to a wall of said housing, said first member at least partially defining a volute having inlet and outlet openings communicating with said housing chamber, and a second member which is separate and removable from said first member, said second member defining a cutwater adjacent said outlet opening of said volute.

14. A self-priming centrifugal pump comprising:

a. housing means having peripheral walls and axially spaced end walls which walls define the inner walls of a pumping chamber for containing a supply of liquid,

b. a rotatable shaft extending into said housing means,

c. a centrifugal pump impeller having a central eye and detachably mounted on said shaft for rotation in said housing means,

d. said housing means including means defining:

i. a liquid inlet passage for directing liquid into the eye of said impeller,

ii. a liquid outlet opening communicating with said chamber,

iii. an access opening in a peripheral housing wall opening into said chamber laterally spaced from the axis of rotation of said impeller,

e. removable closure means covering said access opening,

f. scroll means disposed circumferentially about said impeller in said chamber,

g. said scroll means having:

i. at least an outer circumferential wall portion spaced inwardly from said inner walls of said housing, Y i

ii. inner walls defining volute chamber in which said impeller is disposed,

iii. an inlet priming opening through a circumferential wall of said scroll means communicating with said chamber and saidvolute,

iv. a discharge openingcommlunicating said volute to the interior of said chamber at a location spaced inwardly from said liquid outlet opening of said housing,

h. and means detachably connecting said scroll means to said housing means so that said scroll means can be removed from said chamber through said access opening.

15. A self-priming centrifugal pump as claimed in claim 14 wherein said scroll means comprises at least two separable members, one of said members defining a cutwater in said volute adjacent said discharge opening of said scroll means, said one member being located adjacent said access opening and being removable from said chamber through said access opening without removing the other of said separable members.

16. A self-priming centrifugal pump as claimed in claim 15 wherein said one member is carried by said closure member 17. A self-priming centrifugal pump as claimed in claim 15 wherein said cutwater is coated with a nonmetallic, abrasion-resistant material.

18. A self-priming centrifugal pump comprising:

a. housing menas having peripheral walls and axially spaced walls forming inner walls of a pumping chamber for containing 1 supply of liquid,

b. a rotatable shaft extending into said housing means,

c. a centrifugal pump impeller detachably mounted on said shaft for rotation in said housing means,

d. said housing means having a liquid inlet opening, a liquid outlet opening communicating with said chamber, and an access opening laterally spaced from the axis of rotation of said impeller in a peripheral housing wall and through which said impeller is removable from said chamber,

e. removable closure means for coveringsaid access opening,

f. scroll means formed by at least two separable members disposed circumferentially. about said impeller and having:

i. at least an outer circumferential surface spaced inwardly from said inner walls of said housing,

ii. inner walls which define a volute chamber in which said impeller is disposed,

iii. means defining a discharge opening communicating said volute chamber to the interior of said pumping chamber at a location spaced radially inwardly from said liquid outlet opening of said housing,

iv. an inlet priming opening through a circumferential wall communicating said chamber to said volute,

v. a cutwater in said volute adjacent said discharge opening and defined by one of said separable members,

g. means detachably connecting said scroll means to said housing means so that said scroll means can be impeller and defining an opening through which inlet fluid flows to the eye of said impeller, and,

means detachably connecting said wear plate to said housing means so that it can be removed from said chamber through said access opening after removal of said one separable member of said scroll means.

UNITED STATES PATENT OFFICE (1|. 1li'll FHJA'IE OF (1Ul.{I {lfi(1'll( )N Patent l 8. 181 Dated December 11, 1973? Inventor(s) Stanley 13. Mcl arlin It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 32, "impelller" should be -impeljler--;

Column 2, line 5, "a" should be -the--;

o u n 3, line 11, "centrugal'? should be --centrifugal-;

Column 5, line 57, "78 'f should be -74- Column 10, line 33;, "menas" should be -means-r--;

Column 10, line 35, "1" should be --a--.

Signed and sealed this 15th day of Aprilv 197M.

(SEAL) Attest:

EDWARD M.I"LETCHER,JR; G. MARSHALL DANN Attesting Officer Commissioner of Patents roRmpohosouo-est v v I QQ Govhpfig ((11.1 GOVERNMENY PR lNTING OFFICE: 19! 0-366-3." 

1. In a centrifugal pump having a pumping assembly comprising a rotatable impeller, an impeller drive shaft, scroll means circumferentially surrounding the impeller, and plate means on an axial side of the impeller; the improvement comprising a pump housing for said pumping assembly comprising: a. a first housing wall portion defining an inlet opening; b. a second housing wall portion defining an impeller drive shaft supporting opening in which the impeller drive shaft is supported for rotation about an axis extending through said first and second walls; c. a discharge opening through which liquid is discharged from said housing; d. at least part of the scroll means detachably connected to one of said first and second housing wall portions; e. the other of said first and second housing wall portions supporting the plate means by a detachable connection; f. a third housing wall portion spaced laterally from said axis and defining an access opening through which the impeller, the plate means and said at least part of the scroll means are removable from said housing; and, g. closure means detachably connected to the housing across said access opening.
 2. The pump claimed in claim 1 wherein said closure means comprises a closure member engaged with said housing across said access opening and a clamp device for urging said closure member into sealing engagement with said housing.
 2. scroll means extending circumferentially about said impeller and defined by at least one scroll member detachably connected to said housing;
 3. a wear plate member detachably supported in said housing adjacent an axial side of said impeller and defining an opening through which inlet fluid flows to said impeller; and, d. said housing defining an access opening along a side thereof laterally spaced from said axis, and said wear plate member, said at least one scroll member and said impeller removable from said chamber through said access opening.
 3. The pump claimed in claim 2 wherein one of said first and second wall portions of said housing defines openings through which mounting members extend to said at least part of the scroll means, said mounting members being accessible from the exterior of said housing to permit said at least part of the scroll means to be detached from the housing wall portion.
 4. The pump claimed in claim 1 wherein said housing further includes a liquid inlet assembly supported by said first housing wall portion, said inlet assembly defining a supporting surface for said plate means in said housing.
 5. The pump claimed in claim 4 wherein said plate means is connected to said inlet assembly by fasteners which extend from said plate means through said assembly to a location on the exterior of said housing, said fasteners detachable from said exterior location.
 6. In a centrifugal pump: a. a pump housing defining a chamber having an inlet opening and a discharge opening; b. a pumping assembly supported by said housing in said chamber for drawing liquid through said inlet opening and discharging liquid from said housing through said discharge opening; c. said pumping assembly comprising;
 7. The pump claimed in claim 6 wherein said at least one scroll member is maintained in position in said housing by a clamp device secured to an exterior wall of said housing.
 8. The pump claimed in claim 7 wherein said at least oNe scroll member defines a cut water of said scroll means, and further including a coating of nonmetallic abrasion resistant material extending over at least said cut water portion of said one scroll member.
 9. The pump claimed in claim 8 wherein said one scroll member is integral with a closure member for said access opening, said coating of resilient material extending over at least part of said closure member to seal the juncture of said closure member and said housing about said access opening.
 10. In a centrifugal pump: a. a housing defining a chamber; b. said housing having an inlet passage, a discharge opening, a shaft opening, and an access opening; c. a rotatable shaft extending into said housing through said shaft opening; d. an impeller removably mounted on said shaft in said chamber for rotation on an axis; e. scroll means removably connected to said housing and defining an impeller chamber in which said impeller is disposed; f. a wear plate removably mounted in said chamber adjacent said impeller and defining a port communicating said inlet passage to the eye of said impeller; g. said access opening being laterally spaced from said axis so that said impeller, scroll means and wear plate can be removed from said housing chamber without disconnecting plumbing communicating with said inlet passage and said discharge opening; and, h. removable closure means for closing said access opening.
 11. A pump as claimed in claim 10 wherein said inlet passage extends in substantial alignment with said axis.
 12. A pump as claimed in claim 10 including a tubular body defining said inlet passage, and means detachably connecting said body to a wall portion of said housing.
 13. A pump as claimed in claim 10 wherein said scroll means comprises a first member detachably connected to a wall of said housing, said first member at least partially defining a volute having inlet and outlet openings communicating with said housing chamber, and a second member which is separate and removable from said first member, said second member defining a cutwater adjacent said outlet opening of said volute.
 14. A self-priming centrifugal pump comprising: a. housing means having peripheral walls and axially spaced end walls which walls define the inner walls of a pumping chamber for containing a supply of liquid, b. a rotatable shaft extending into said housing means, c. a centrifugal pump impeller having a central eye and detachably mounted on said shaft for rotation in said housing means, d. said housing means including means defining: i. a liquid inlet passage for directing liquid into the eye of said impeller, ii. a liquid outlet opening communicating with said chamber, iii. an access opening in a peripheral housing wall opening into said chamber laterally spaced from the axis of rotation of said impeller, e. removable closure means covering said access opening, f. scroll means disposed circumferentially about said impeller in said chamber, g. said scroll means having: i. at least an outer circumferential wall portion spaced inwardly from said inner walls of said housing, ii. inner walls defining volute chamber in which said impeller is disposed, iii. an inlet priming opening through a circumferential wall of said scroll means communicating with said chamber and said volute, iv. a discharge opening communicating said volute to the interior of said chamber at a location spaced inwardly from said liquid outlet opening of said housing, h. and means detachably connecting said scroll means to said housing means so that said scroll means can be removed from said chamber through said access opening.
 15. A self-priming centrifugal pump as claimed in claim 14 wherein said scroll means comprises at least two separable members, one of said members defining a cutwater in said volute adjacent said discharge opening of said scroll means, said one member being locaTed adjacent said access opening and being removable from said chamber through said access opening without removing the other of said separable members.
 16. A self-priming centrifugal pump as claimed in claim 15 wherein said one member is carried by said closure member
 17. A self-priming centrifugal pump as claimed in claim 15 wherein said cutwater is coated with a non-metallic, abrasion-resistant material.
 18. A self-priming centrifugal pump comprising: a. housing menas having peripheral walls and axially spaced walls forming inner walls of a pumping chamber for containing 1 supply of liquid, b. a rotatable shaft extending into said housing means, c. a centrifugal pump impeller detachably mounted on said shaft for rotation in said housing means, d. said housing means having a liquid inlet opening, a liquid outlet opening communicating with said chamber, and an access opening laterally spaced from the axis of rotation of said impeller in a peripheral housing wall and through which said impeller is removable from said chamber, e. removable closure means for covering said access opening, f. scroll means formed by at least two separable members disposed circumferentially about said impeller and having: i. at least an outer circumferential surface spaced inwardly from said inner walls of said housing, ii. inner walls which define a volute chamber in which said impeller is disposed, iii. means defining a discharge opening communicating said volute chamber to the interior of said pumping chamber at a location spaced radially inwardly from said liquid outlet opening of said housing, iv. an inlet priming opening through a circumferential wall communicating said chamber to said volute, v. a cutwater in said volute adjacent said discharge opening and defined by one of said separable members, g. means detachably connecting said scroll means to said housing means so that said scroll means can be removed from said chamber through said access opening, h. said one separable member which defines said cutwater being located adjacent said access opening and being removable through said access opening without removing the other of said separable members, i. a wear plate located adjacent an axial side of said impeller and defining an opening through which inlet fluid flows to the eye of said impeller, and, j. means detachably connecting said wear plate to said housing means so that it can be removed from said chamber through said access opening after removal of said one separable member of said scroll means. 